The Anglican Archbishop told an overflow crowd at St. Sabina's Church that people must seek peace, reconciliation and forgiveness. Parishioners waited for hours to hear Tutu, who is making few appearances during his U.S. visit.
Tutu, 70, said Rev. Michael Pfleger, a white Catholic priest who has led a mostly African-American congregation for more than 20 years, would participate in an annual anti-racism, human rights forum at the University of Chicago named in honor of Tutu.
The inaugural forum will be held during the fall term, university officials said.
Pfleger called Tutu, who was diagnosed with prostate cancer in 1996, "a living history of hope."
During his address, the diminutive Tutu described life in his homeland under apartheid.
"Everything was segregated," he said. "When I become archbishop in 1986, the official residence of the archbishop of Cape Town was in a white area. It was a criminal offense for the new archbishop to ... go and reside in his official residence. I told the government, 'Tough Luck.'"
Tutu said he voted for the first time in 1994 when Nelson Mandela was elected the first black president of South Africa. Tutu, a visiting professor at Harvard University, said Americans must confront racism and injustice and not remain neutral on the sidelines.
"Think of how greatly enriched this country can be, will be, when all its people have the opportunity to develop at the fullest possible extent," said Tutu.
In 1995, Tutu led South Africa's historic Truth and Reconciliation Commission, which examined the atrocities committed during apartheid. "We learned in South Africa that you will never get true security, true peace, or true stability though the barrel of a gun," he said.